I disagree with this. I believe OP was under the impression he HAD to build a motor to reliably support 700whp, which is not true. His subsequent responses also made me think this. If you WANT to build a motor, then sure. I just did it with an LS6 because I hadn't built a motor before and wanted to. But WANT does not equal MUST.

 

 

Yep. Mostly just to learn and be able to say I built and tuned that thing. I will consider what ddnspider is suggesting. The problem I have is that I'm probably going through everything except the short block anyway while still risking the high mileage short block I get could let go immediately. A lot of work and money considering the price of...gaskets, fasteners, refreshing heads, oil pump, valve train, etc etc. while kind of playing the lottery on that high mileage junk yard motor. Not saying the same couldn't happen with a short block I build LOL. I wouldn't be totally going it alone I have friends I can ask for help along the way that have built motors and do all their own work.

It's a lot to consider and I have time to think about it as it would most likely be a winter time project for me.

 

read fool!!!

 

He asked about 58x and knock sensors and cam on a gen 4. By that I took it that he would consider a jy gen 4. . . Just like his last reply said.....fool.

 

I have a lot to think about as you can see by all the different opinions in this thread. Luckily I have a good running engine right now so I'm in no hurry. Chances are I'm going to want to run more boost by next spring and at that point I'll be reaching what many consider the ragged edge of what a sbe ls1 can take. That is the reason I'm doing planning now.

 

Always smart to plan ahead. Not to mention you can sell your good running ls1 to pay for part of whatever you do.

 

LOL

A good condition junk yard gen 4 with the ring gaps opened up would last a lot longer than you might think. The same principles still apply that allow them to go so long in the first place, no matter what power level there is oil between everything and nothing touches etc. The only thing that will have a harder life really is the rings and head bolts. But the rings will still go a good long time and if you don't detonate or try to make 1200 all day every day the head bolts will likely be fine, and if not slap some ARP's in it. If you aren't revving to the moon you need to do nothing to the bottom end, and if you want to rev real high a set of rod bolts takes care of that. I think some people forget that a gen 4 motor holds as much or more power than a fully forged motor did pre 2000's without issue, the pistons maybe not so much, but without ring butting they go well beyond 1k hp no problem.

To put it another way, there isn't much that a forged bottom end will take that a gen 4 wont (under 1k or so rwhp). And detonation etc will kill either no problem. So that's why people steer you away from it. And keep in mind engine masters/richard holdener did 1600 hp on a 6.0 and still didn't break it.

I'm all for you building your own motor, but if you want to make reliable power on a budget JY motor is the way to go. And if it wears out after a couple of years, buy another $500 motor. Even in that scenario you still have over 3k left and still had tons of fun and made the power you wanted. Also the lack of give a F is nice, usually equates to more hold my beer and watch this moments, aka memories.

Definitely lots to think about, it's your build do it your way.

 

The last time I remember seeing a topic on Summit LS engine blocks I seem to remember most recommended having a quality machine shop do a finish hone on the block.

 

I bought a 6.0 summit iron block when they still had them. They were advertised as .030. It came packed extremely well in a crate. I think it ha an ATK tag riveted to it, but I don't fully remember. After I bought it I read all kinds of horror stories about them (summit blocks) so I asked the machine shop to look at it. He dial bore mic'd it and checked a bunch of other stuff and said it was good to go - no charge or work needed. Its been a very slow project but its finally getting ready to be started up (3 years in the making). we will see how it goes. Other people were saying their machinists said the blocks they got from summit needed 1k+ worth of work...who knows

 

That was a major factor in why I decided to start tuning on this motor. I figured if I hurt this motor it wouldn't be a big deal as compared to starting with an expensive built motor and hurting it because I don't know how to tune. Now I feel pretty confident in my tuning ability, but still don't see the point in spending a ton of cash on a built motor with expensive heads on a forced induction setup. I figure let the blower do the work. I'm warming up to the junk yard motor idea so I'll check around and see what they go for in my area. I also know Thompson sells a 6.0 iron short block for about $3g that has a stock crank, rods, and forged pistons that would fit my goals nicely. A lot to think about.

 

I agree on letting the blower do the work, and keep in mind the more basic the heads and cam, the more of your boost is being held in the intake and not making it to the cylinder, so that boost number isn't really the most important number. I say that because you said you were wanting to go to 15 pounds, and boost pressure is a measurement of restriction. If you open up the heads and run a larger cam the boost will drop and the power will rise.

Anyway, I can see why you'd want an all new motor, it would suck to waste time on a bad motor if the used one was crap. I still say build your motor, you started this cause you wanted to learn and build.

If nothing else, buy a junkyard motor and play with taking it apart and beating on it and be building a new one at the same time

 

This might be the best compromise. Buy a gen 4 SB, take it apart to replace the bearings and re-ring it. Still much cheaper than a built motor, but still getting to build the motor. lol.

 

I understand that boost is a measure of pressure or restriction. I mention 15 psi and a 700 rwhp through an auto trans as a general idea of the combo I want. Using a 370 with 243 heads, ls6 intake, and a well matched streetable cam for the combo on E85 should get me close to that goal. The D1X is rated at 1000 hp at the crank and I have no doubts it can make 700 rwhp within it's efficiency range. Depending on how everything flows I don't know what blower speed I will need to achieve 15 psi on that combo, but I could start out low and work my way up.

 

From my research some claim that some of the 2004 model year ls1 engines do have the floating gen4 rods. I have no idea how to verify that, but I could just keep pushing this motor until I find out LOL

 

You might PM Detoxx about the D1X. I think he's north of 800whp on his.

 

I'm aware of his car I believe he might be over 900 rwhp now, but it's a manual.

 

You won't lose 200whp because you're an auto higher you rev more hp you make for a given pulley. I think your goal is sound.

 

The LPE 58x to 24x converter box works great in my experience. I have one on my 416 in my TA. It takes a couples of seconds to sync and crank otherwise you'd never know it's there. If it doesn't crank in 1-2 seconds, I usually let of the ignition and crank 1-2 seconds and it fires right up. If you use one be sure to mount the box away from hot spots as much as possible.